Just to let you know:
I followed the instructions on http://talk.maemo.org/showpost.php?p...6&postcount=41 and bricked my phone.
I had power kernel 46 installed before that, so this might have been the issue. Anyway, afterwards I rebooted and got into u-boot. It always came to the point of " starting kernel..." and then restarted. With the keyboard open, I could get into the already installed backupmenu, how ever could not restore the backups as it could not mount the partitions

The only to get it working again was to flash it
Its not a big deal, as I always have a backup, but its a pain to reload everything again.

So if somebody can let me know what I did wrong, I would like to give it another try.